BAGHDAD - Building a self-sustaining security force in Iraq is being hobbled by concerns of creating a sectarian Sunni force, the Washington Post reported Monday.

Iraqi and U.S. officials told a Post correspondent in Baghdad about 80 percent of volunteers to the military and police forces are Sunni Muslims, which has created a fear they could eventually mount an armed opposition.

Some 51,000 people in 12 of Iraq's 18 provinces are registered under a military designation of "Concerned Local Citizens," and have been screened and had their names, fingerprints and other biometric data recorded by the U.S. military, said British counterinsurgency expert Maj. Gen. Paul Newton.

While U.S. commanders claim the coalition is not forming a Sunni militia, Iraqi leaders -- mostly Shiite -- complain paying the fighters about $300 a month is tantamount to arming them, the report said.

In support of the recruiting bid, Lt. Gen. Raymond Odierno, the second-highest U.S. commander in Iraq, said over a recent 15-day period, volunteers had provided tips that led to the recovery of 37,000 pounds of explosives, 2,000 artillery rounds, 500 rockets, nearly 500 armor-piercing projectiles and components, and hundreds of rifles, grenades and suicide vests, the Post said.